Bottom Line:
The sorption was reasonably explained with Langmuir and Freundlich isotherms.The thermodynamic parameters such as ΔG0, ΔH0, ΔS0 and Ea were calculated in order to understand the nature of sorption process.The sorption process was found to be controlled by pseudo-second order and intraparticle diffusion models.

ABSTRACTThe adsorption potential of iron acetate coated activated alumina (IACAA) for removal of arsenic [As (III)] as arsenite by batch sorption technique is described. IACAA was characterized by XRD, FTIR, EDAX and SEM instruments. Percentage adsorption on IACAA was determined as a function of pH, contact time and adsorbent dose. The study revealed that the removal of As (III) was best achieved at pH =7.4. The initial As (III) concentration (0.45 mg/L) came down to less than 0.01 mg/L at contact time 90 min with adsorbent dose of 1 g/100 mL. The sorption was reasonably explained with Langmuir and Freundlich isotherms. The thermodynamic parameters such as ΔG0, ΔH0, ΔS0 and Ea were calculated in order to understand the nature of sorption process. The sorption process was found to be controlled by pseudo-second order and intraparticle diffusion models.

Mentions:
The surface morphology of iron acetate coated activated alumina (IACAA) adsorbentbefore and after treatment with arsenic samples were examined by scanningelectron microscope (SEM). SEM photographs before and after treatment witharsenic are given in Figures 5(a) and (b)respectively. It is clear that the surface morphology of these two samples isdifferent which confirms the arsenic sorption onto the IACAA adsorbents. X-raydiffraction patterns of activated alumina, IACAA and arsenic adsorbed IACAA aregiven in Figures 6(a), (b) and (c) respectively.Crystalline phases were identified by software database published by the JointCommittee on Powder Diffraction Standards (JCPDS). The main mineral phases ofalumina, iron and arsenic sorption on IACAA respectively were identified asAl2O3 (JCPDS-79-1557), AlFeO3(JCPDS-84-2154) and FeAsO4 (JCPDS-78-1545). The FTIR spectra of IACAAbefore and after adsorbing As (III) in aqueous solution are shown inFigures 7(a) and (b). In the Figure 7(a) IR spectrum of IACAA shows distinct bands at 1748,1638, 1459 and 1383 cm-1. As described elsewhere [34], these bands arise from Fe-OH stretching and banding vibration frompart of hydroxyl groups, which are converted from the iron oxide in the forms oftransient complex species such as Fe-OH, Fe(OH)2 or FeO(OH) on thesurface of IACAA. The As (III) adsorption leads to promote intensity of thespectrum by an order of magnitude without many changes in the individualpositions of bands. But the IR band in Figure 7(a)that shifts from 698 cm-1 in case of IACAA to 782 cm-1upon As (III) adsorption is attributed to the As-O stretching band followingpartial substitution of Fe3+ by As3+. These results are inreasonable agreement with the earlier studies of As (III) sorption to Fe and Aloxide [35]. EDAX analysis of adsorbents after adsorption of arsenic showed thepresence of oxygen, arsenic, alumina and iron. The graphical representation isdepicted in Figure 8.

Mentions:
The surface morphology of iron acetate coated activated alumina (IACAA) adsorbentbefore and after treatment with arsenic samples were examined by scanningelectron microscope (SEM). SEM photographs before and after treatment witharsenic are given in Figures 5(a) and (b)respectively. It is clear that the surface morphology of these two samples isdifferent which confirms the arsenic sorption onto the IACAA adsorbents. X-raydiffraction patterns of activated alumina, IACAA and arsenic adsorbed IACAA aregiven in Figures 6(a), (b) and (c) respectively.Crystalline phases were identified by software database published by the JointCommittee on Powder Diffraction Standards (JCPDS). The main mineral phases ofalumina, iron and arsenic sorption on IACAA respectively were identified asAl2O3 (JCPDS-79-1557), AlFeO3(JCPDS-84-2154) and FeAsO4 (JCPDS-78-1545). The FTIR spectra of IACAAbefore and after adsorbing As (III) in aqueous solution are shown inFigures 7(a) and (b). In the Figure 7(a) IR spectrum of IACAA shows distinct bands at 1748,1638, 1459 and 1383 cm-1. As described elsewhere [34], these bands arise from Fe-OH stretching and banding vibration frompart of hydroxyl groups, which are converted from the iron oxide in the forms oftransient complex species such as Fe-OH, Fe(OH)2 or FeO(OH) on thesurface of IACAA. The As (III) adsorption leads to promote intensity of thespectrum by an order of magnitude without many changes in the individualpositions of bands. But the IR band in Figure 7(a)that shifts from 698 cm-1 in case of IACAA to 782 cm-1upon As (III) adsorption is attributed to the As-O stretching band followingpartial substitution of Fe3+ by As3+. These results are inreasonable agreement with the earlier studies of As (III) sorption to Fe and Aloxide [35]. EDAX analysis of adsorbents after adsorption of arsenic showed thepresence of oxygen, arsenic, alumina and iron. The graphical representation isdepicted in Figure 8.

Bottom Line:
The sorption was reasonably explained with Langmuir and Freundlich isotherms.The thermodynamic parameters such as ΔG0, ΔH0, ΔS0 and Ea were calculated in order to understand the nature of sorption process.The sorption process was found to be controlled by pseudo-second order and intraparticle diffusion models.

ABSTRACTThe adsorption potential of iron acetate coated activated alumina (IACAA) for removal of arsenic [As (III)] as arsenite by batch sorption technique is described. IACAA was characterized by XRD, FTIR, EDAX and SEM instruments. Percentage adsorption on IACAA was determined as a function of pH, contact time and adsorbent dose. The study revealed that the removal of As (III) was best achieved at pH =7.4. The initial As (III) concentration (0.45 mg/L) came down to less than 0.01 mg/L at contact time 90 min with adsorbent dose of 1 g/100 mL. The sorption was reasonably explained with Langmuir and Freundlich isotherms. The thermodynamic parameters such as ΔG0, ΔH0, ΔS0 and Ea were calculated in order to understand the nature of sorption process. The sorption process was found to be controlled by pseudo-second order and intraparticle diffusion models.